Also, solar and wind are intermittent, and therefore not ideal for dealing with real-time grid demand. However, that may make them ideal for passive carbon capture

I think that’s a huge part of the long term solution: intentionally building overcapacity so that lower production days still produce enough energy to meet needs, but especially sunny or windy days have surplus that needs to be used. If the intermittent energy surplus meets a carbon-fixing method to consume that surplus energy, then we can have carbon capture without that energy use displacing a reduction of greenhouse emissions elsewhere.